How to mount context-referenced Tomcat application with mod_jk?

Question

I have an WAR application running in Tomcat at /foo context, meaning that its URL is http://example.com:8080/foo. Now I'm trying to connect Apache HTTP Server to Tomcat through mod_jk. This is my workers.properties file:

worker.list=foo
worker.foo.port=8009
worker.foo.host=localhost
worker.foo.type=ajp13
worker.foo.mount=/foo/*

Works fine, but at this URL: http://example.com/foo. I would like it to be at http://example.com. What am I missing?

ps. This is my mod-jk.conf, which is included into httpd.conf:

LoadModule jk_module modules/mod_jk.so
JkWorkersFile /usr/local/tomcat/conf/workers.properties
<VirtualHost *:80>
  ServerName foo.example.com
  JkMount /* foo
</VirtualHost>

Answer 1

You basically have two options:

1. Modify your Tomcat configuration to mount the WAR at the root. How this is done depends on how exactly you're deploying your application. This is the cleaner approach unless there's some preventing factor.
2. Handle the problem on the Apache side by using mod_rewrite to rewrite URLs starting with / to /foo, at which point it will be passed through your JkMount to Tomcat

For the second option, your Apache configuration would look something like this:

# Turn on mod_rewrite
RewriteEngine On
# This is the rule. Use regexp to match any URL beginning with /, and rewrite it to
# /foo/remaining_part_of_URL. The [PT] (pass-through) is necessary to make rewritten
# requests go through JkMount
RewriteRule ^/(.*) /foo/$1 [PT]

# Forward all URLs starting with foo to Tomcat
JkMount /foo/* worker

(this isn't actually tested, hope it works as is!). You may also need to enable mod_rewrite in your Apache (check out your distribution, a mods-enabled directory might be the answer).

And if you need to know more about mod_rewrite (quite a powerful beast), go here: http://httpd.apache.org/docs/2.0/mod/mod_rewrite.html#rewriterule